This invention relates to a miniature motor coil used, for example, as the drive coil of a brushless motor and the so-called transistor motor or as a power generating coil, the so-called FG coil.
The coils of these conventional kinds of motors were in the past made of so-called wound wire, or made by winding copper wire with a winding machine. With the miniaturization of the motor, it was desired to increase the current flowing through the coil and apply a strong magnetic field to the coil in order to improve the efficiency of the motor. In the conventional wire wound coil, the percentage of the space occupied by the coil conductor per unit space is reduced as the coil becomes smaller and accordingly the motor efficiency is lowered. For this reason, there was a limit in the miniaturization of the motor. It was difficult to obtain a small motor which possesses a considerable degree of output. Moreover, in conventional cases, it was necessary that the coil was wound by the wire winder and a plural number of coils thus wound were installed according to a predetermined layout, and the work to install a plural number of coils in a predetermined arrangement for very small motors, for example, for the motors whose motor cases are about 10 mm in diameter became very difficult. For this reason, there was a drawback of reducing the motor output due to the failure in keeping motor coils in correct arrangement.
An object of this invention is to offer a miniature motor coil capable of obtaining efficient miniature motors due to a large conductor occupation rate per unit space.
Another object of this invention is to offer a miniature motor coil which can be assembled into a motor with a high positional accuracy.
Still another object of this invention is to offer a miniature motor coil which has a high conductor occupation rate per unit space and is easy to manufacture.
Still another object of this invention is to offer a miniature motor coil which has a high conductor occupation rate per unit space and the conductor of which is uniform in thickness at each section.
Still another object of the invention is to offer a miniature motor coil which is formed on both surfaces of an insulating sheet and which enables connection between the two coils to be performed easily.